Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Instantaneous measurement of field quadrature moments and entanglement

Pavel Lougovski, HERBERT WALTHER, E. Solano

Published Jun 1, 2006• 13 citations
OpenAlex

Abstract

We present a method of measuring expectation values of quadrature moments of a multimode field through two-level probe "homodyning". Our approach is based on an integral transform formalism of measurable probe observables, where analytically derived kernels unravel efficiently the required field information at zero interaction time, minimizing decoherence effects. The proposed scheme is suitable for fields that, while inaccessible to a direct measurement, enjoy one and two-photon Jaynes-Cummings interactions with a two-level probe, like spin, phonon, or cavity fields. Available data from previous experiments are used to confirm our predictions.

Related papers

Instantaneous measurements of quadrature moments of cavity fields with strongly driven atoms

Xu‐Bo Zou, Yuli Dong, Guang‐Can Guo

We propose a scheme for measuring the mean value of quadrature moments of one- and two-mode cavity fields by considering the resonant atom–cavity interaction in the presence of strong classical driving fields. With the aid of strong classical fields, it is easy to realize the quadrature operators for cavity fields, which are correlated to the internal state of the two-level atom. It is shown that the mean value of quadrature moments of cavity fields is determined by the time derivative of the population of the internal state at the initial interaction time. The scheme can be directly used to test quantum entanglement of two-mode cavity fields.

Journal of Physics B Atomic Molecular and Optical Physics•Sep 4, 2006•0 citations

Noise-Free Measurement of Harmonic Oscillators with Instantaneous Interactions

Marcelo França Santos, G. Giedke, E. Solano

We present a method of measuring the quantum state of a harmonic oscillator through instantaneous probe-system selective interactions of the Jaynes-Cummings type. We prove that this scheme is robust to general decoherence mechanisms, allowing the possibility of measuring fast-decaying systems in the weak-coupling regime. This method could be applied to different setups: motional states of trapped ions, microwave fields in cavity or circuit QED, and even intracavity optical fields.

arXiv:quant-ph/0606004•Physical Review Letters•Jan 8, 2007•14 citations

The Measurement on High-order Photon Number and its Variances

Yuzhen Li

A method of measuring expectation values of quadrature moments of a multimode field is introduced through two-levels probe presented by Enrique Solano et al.Similarly,the measurements of expectation values of high-order photon numbers and variances are also discussed.It is pointed out that high-order photon numbers(n~k) and variances are expanded in terms of normal order of creation(a~+) and annihilation(a) operator of night field,and we have derived the relation between high-order photon numbers and variances and probe observables.The results show that information of high-order photon numbers and variances only contain the first or the second derivative,at τ=0,of the measured probe population.Note that knowing derivative at τ=0 only requires knowing the function in a vicinity and the influence of decoherence is minimized.

•Jan 1, 2006•0 citations

Reconstruction of a multimode entangled state using a two-photon phase-sensitive linear amplifier

Mashhood Ahmad, Shahid Qamar, Muhammad Suhail Zubairy

We propose a model for the measurement of an arbitrary multimode entangled state of the cavity field using two-photon correlated emission laser. We consider two cases: (a) The modes have different frequencies and are detected separately and (b) the modes consist of two orthogonal polarization states and are detected using a single balanced homodyne detector. The basic idea is to amplify the initial multimode state such that there is no-noise in the quadrature of interest and all the noise is fed into the conjugate quadrature component. The amplified noise-free quadrature is prepared in different phases and then corresponding quadrature distribution is measured. The Wigner function of the initial multimode entangled state is then reconstructed by using inverse Radon transformation. This scheme is insensitive to the noise associated with the nonunit efficiency of the detector in the homodyne detection measurement scheme.

Physical Review A•Apr 23, 2003•11 citations

Direct Measurement of Atomic Entanglement via Cavity Photon Statistics

Nilakantha Meher, Mishkatul Bhattacharya, Anand K. Jha

Abstract An experimental scheme for the measurement of entanglement between two two‐level atoms is proposed. This scheme requires one of the two entangled atoms to interact with a cavity field dispersively, and it is shown that by measuring the zero time‐delay second‐order coherence function of the cavity field, one can measure the concurrence of an arbitrary Bell‐like atomic two‐qubit state. As this scheme requires only one of the atoms to interact with the measured cavity, the entanglement quantification becomes independent of the location of the other atom. Therefore, this scheme can have important implications for entanglement quantification in distributed quantum systems.

arXiv:2204.03891•Annalen der Physik•May 4, 2022•1 citation

Scheme for generating entangled states of two field modes in a cavity

Jonas Larson

This paper considers a two-level atom interacting with two cavity modes with equal frequencies. Applying a unitary transformation, the system reduces to the analytically solvable Jaynes–Cummings model. For some particular field states, coherent and squeezed states, the transformation between the two bare bases, related by the unitary transformation, becomes particularly simple. It is shown how to generate (the highly non-classical) entangled coherent states of the two modes, both in the zero and large detuning cases. An advantage of the zero detuning case is that the preparation is deterministic and no atomic measurement is needed. For the large detuning situation, a measurement is required, leaving the field in either of two orthogonal entangled coherent states.

arXiv:quant-ph/0508090•Journal of Modern Optics•Jun 27, 2006•9 citations
We present a method of measuring expectation values of quadrature moments of a multimode field through two-level probe "homodyning". Our approach is based on an integral transform formalism of measurable probe observables, where analytically derived kernels unravel efficiently the required field information at zero interaction time, minimizing decoherence effects. The proposed scheme is suitable for fields that, while inaccessible to a direct measurement, enjoy one and two-photon Jaynes-Cummings interactions with a two-level probe, like spin, phonon, or cavity fields. Available data from previous experiments are used to confirm our predictions.
We propose a scheme for measuring the mean value of quadrature moments of one- and two-mode cavity fields by considering the resonant atom–cavity interaction in the presence of strong classical driving fields. With the aid of strong classical fields, it is easy to realize the quadrature operators for cavity fields, which are correlated to the internal state of the two-level atom. It is shown that the mean value of quadrature moments of cavity fields is determined by the time derivative of the population of the internal state at the initial interaction time. The scheme can be directly used to test quantum entanglement of two-mode cavity fields.
A method of measuring expectation values of quadrature moments of a multimode field is introduced through two-levels probe presented by Enrique Solano et al.Similarly,the measurements of expectation values of high-order photon numbers and variances are also discussed.It is pointed out that high-order photon numbers(n~k) and variances are expanded in terms of normal order of creation(a~+) and annihilation(a) operator of night field,and we have derived the relation between high-order photon numbers and variances and probe observables.The results show that information of high-order photon numbers and variances only contain the first or the second derivative,at τ=0,of the measured probe population.Note that knowing derivative at τ=0 only requires knowing the function in a vicinity and the influence of decoherence is minimized.
We propose a model for the measurement of an arbitrary multimode entangled state of the cavity field using two-photon correlated emission laser. We consider two cases: (a) The modes have different frequencies and are detected separately and (b) the modes consist of two orthogonal polarization states and are detected using a single balanced homodyne detector. The basic idea is to amplify the initial multimode state such that there is no-noise in the quadrature of interest and all the noise is fed into the conjugate quadrature component. The amplified noise-free quadrature is prepared in different phases and then corresponding quadrature distribution is measured. The Wigner function of the initial multimode entangled state is then reconstructed by using inverse Radon transformation. This scheme is insensitive to the noise associated with the nonunit efficiency of the detector in the homodyne detection measurement scheme.
Abstract An experimental scheme for the measurement of entanglement between two two‐level atoms is proposed. This scheme requires one of the two entangled atoms to interact with a cavity field dispersively, and it is shown that by measuring the zero time‐delay second‐order coherence function of the cavity field, one can measure the concurrence of an arbitrary Bell‐like atomic two‐qubit state. As this scheme requires only one of the atoms to interact with the measured cavity, the entanglement quantification becomes independent of the location of the other atom. Therefore, this scheme can have important implications for entanglement quantification in distributed quantum systems.
This paper considers a two-level atom interacting with two cavity modes with equal frequencies. Applying a unitary transformation, the system reduces to the analytically solvable Jaynes–Cummings model. For some particular field states, coherent and squeezed states, the transformation between the two bare bases, related by the unitary transformation, becomes particularly simple. It is shown how to generate (the highly non-classical) entangled coherent states of the two modes, both in the zero and large detuning cases. An advantage of the zero detuning case is that the preparation is deterministic and no atomic measurement is needed. For the large detuning situation, a measurement is required, leaving the field in either of two orthogonal entangled coherent states.